An orthopedic surgeon accused of faking operations surrendered his medical license voluntarily Monday and has admitted to guilt in some of the cases against him, according to New York State court documents.

Dr. Spyros Panos, who formerly worked for the Mid Hudson Medical Group in Poughkeepsie, N.Y., surrendered his license to practice medicine in New York this week following charges of medical misconduct. Panos faced at least 250 counts brought by the state Office of Professional Medical Conduct involving fraud and negligence between 2007 and 2011, the court order showed.

Panos, 44, and his attorneys at Feldman, Kleidman & Coffey did not respond to ABC News' requests for comment. Representatives for the Mid Hudson Medical Group also failed to return calls for comment.

Larry Hughes, a spokesman for Saint Francis Hospital in Poughkeepsie, where Panos performed many of the surgeries under investigation, said he was unaware of the surrender filing and couldn't comment.

In his response to the license surrender order, Panos admitted that he failed to render appropriate care, didn't maintain accurate medical records and submitted bills for seven former patients for which he was not entitled to payment. The identities of the patients were redacted from court documents to maintain their privacy.

The response also stated that Panos cannot "successfully defend against" at least one alleged act of misconduct "in full satisfaction of the charges" and that the surrender allows him to "resolve this matter without the various risks and burdens of a hearing on the merits."

"It is a rare occurrence for the OPMC to put this type of pressure on a physician and for the physician to lose his license," said J.T. Wisell, an attorney for 154 of the more than 250 plaintiffs who have filed lawsuits accusing Panos of performing botched or unnecessary surgeries, or pretending to perform surgeries that never actually took place.

The Federation of State Medical Boards, which represents 70 state medical boards, reported that of the three quarter of a million practicing physicians in the United States, only 1,905 of them lost their licenses to practice medicine in 2011. Of the more than 88,000 physicians who practiced in New York State that same year, just 185 -- less than one percent -- lost their licenses.

Panos was terminated from his employer, Mid Hudson Medical Group, in 2011 and is also the subject of a criminal investigation by the U.S. Attorney's Office, although he has not been charged with a criminal offense, Wisell said.

His alleged victims say they are grateful that he's out of business, at least in New York.

"I'm glad someone finally stopped him," said Debra Cole, a retired telephone company technician who is suing Panos for allegedly performing two faked knee surgeries and causing her years of unnecessary pain. "To do everything he's allegedly done and to be able to continue to operate on other people, it was just terrible."

Debra Nenni McNamee, whose mother, Constance Nenni, died less than 24-hours after having an alleged "phantom" knee surgery performed by Panos said she hoped Panos' license surrender would start a domino effect.

"Now maybe the other medical professionals and facilities involved who allowed him to do what he did will be held accountable or come forward to prove they are not guilty," she said.

Arthur Caplin, the director of medical ethics at NYU Langone Medical Center and a former non-MD representative with the New York State medical licensing board, said he also found it troubling that others besides Panos aren't under investigation.

"You can't perform this many suspect surgeries without the cooperation of many other people," he said.

Brian Brown, McNamee's attorney, said Panos used patients like her mother as human cash registers, scheduling as many as 22 surgeries a day. The average orthopedic surgeon typically schedules no more than 32 procedures a month, according to American Academy of Orthopaedic Surgeons statistics.

Attorneys Brown and Wisell noted that clients with potential cases against Panos began flooding their offices with calls immediately after journalist Sarah Bradshaw wrote about the first few lawsuits for the Poughkeepsie Journal in September 2010. Bradshaw said she was tipped off to the litigation from an anonymous source.

Wisell said the latest developments should help the plaintiffs' cases finally move forward after two years. But the lawsuits are by no means a slam dunk because there is still a legal stay in place that prevents plantiff's attorneys from taking sworn statements from any employee and former employee of the Mid Hudson Medical Group or any hospital where Panos practiced, Wisell said.

The stay was put in place for Panos to avoid self incrimination in the federal cases of fraud and billing irregularities, Wisell said. Mid Hudson Medical Group and the various hospitals and surgical centers where Panos practiced have submitted billing records, surgical records and surgical schedule logs to plantiff's lawyers but under the stay, are not yet required to directly respond to civil actions, Wisell said.

Brown agreed, stating, "While this demonstrates that Dr. Panos is finally willing to admit some guilt, it is clear from their legal strategy that his former medical-group, MHMG, the hospitals involved and their legal team are not. So they shamelessly continue to drag the victims through a tortured litigation process and avoid taking simple responsibility for their profit-driven failures."

Wisell also noted that Panos still has a license to practice medicine in Virginia. While he is legally obligated to keep the Virginia state medical board up to date about the legal consequences in New York, Wisell said it could take some time before any action was taken and there is no federal mandate that stops Panos from practicing medicine in other states.

McNamee said taking away Panos' license is a start, but it's not enough.

"He wakes up every morning spending the illegal funds he collected while his victims wake up every day in pain," McNamee said. "In my mother's case, all we have are memories."